-> remember the previously loaded serverlist, and use if new one failed
-> show a "loading" serverlist

Create Parameters on world initialisation and set settings of old worlds

Client now informs about incompatible servers from the list, this permits to prevent the protocol movements.
Server announces its supported protocol versions to master server

Fixes #1807: When the server list finishes downloading, the local server
list resets in certain conditions

Fix crash on using cursor keys in client menu without selected server
Add support for non fixed size tabviews